Nuclear reactors generate substantial amounts of radioactive waste material in the form of spent fuel rods which are still highly radioactive. Special containers or casks are needed to transport them to preprocessing plants or for storing them. These casks must act as shields against radioactivity and must be structurally strong and sound as well as inexpensive as possible. Lead is well known to be a good shield against radioactivity but lead is too soft for secure fabrication and fastening. Depleted uranium is better and the shielding material of choice. It is cast into the desired shape and then sandwiched between steel or other structural members to provide the necessary strength and rigidity for the cask. However, castings suffer from voids due to cracks, gas holes, shrink holes and the like, which results in less than the specified thickness of depleted uranium for shielding. In addition, the large castings required are in the range of fifty to sixty thousand pounds while the largest uranium furnaces in current operation have typically no more than a five to six thousand pound capacity. As a result, the casks must be cast in pieces and then securely fastened together in such a way as to not only provide a rigid, unitary container but also so as to provide no clear, unshielded line of sight path through the cask along which radiation could escape.